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The endangered giants that still lurk in the world鈥檚 biggest rivers

The world's fresh waters used to teem with enormous fish. Their numbers are dwindling, but it is not too late to save the river monsters from extinction

By Graham Lawton

30 September 2020 Last updated 2 October 2020

New 精东传媒. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.

Robert Wilson/Wildestanimal/Getty Images

“THEY are the most threatened group of organisms on the planet,” says biologist Ivan Jari膰. “More than 70 per cent of species are critically endangered, some are almost gone.”

He isn’t talking about the usual suspects: great whales, great apes or the corals of the Great Barrier Reef. He is talking about great fish. Specifically, sturgeons and paddlefish. Together they span 27 species, but 17 are in the most precarious category on the red list of endangered species.

Actually, make that 26 species. Earlier this year, a team including Jari膰 that one of the greatest of them all, the giant Chinese paddlefish, is almost certainly no more. It hasn’t been seen in the Yangtze river basin since 2003 and a recent exhaustive search failed to find any. “The chance it still exists is very, very low,” says Jari膰, who is at the Czech Academy of Sciences Institute of Hydrobiology.

Sturgeons are the hardest hit of a group of animals that rarely make the headlines, even in conservation biology circles, but this group is declining faster than any other. They are collectively known as “freshwater megafauna” 鈥 monster fish such as sturgeons, giant catfish, river sharks and rays, along with river dolphins, porpoises, seals, manatees, crocodiles, alligators, snakes, turtles and salamanders.

鈥淭he river megafauna are hidden below the surface of human perception鈥

All told, there are more than 200 species of freshwater megafauna; most are in deep water and some are probably already doomed to extinction. Yet they are largely overlooked by efforts to save…

Article amended on 2 October 2020

Correction:We have changed a photo in this feature because the original was showing the wrong species of paddlefish.

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